The characterization of microstructures is fundamentally important to investigations of amorphization which is induced by ion implantation and recrystallization which occurs by solid-phase, epitaxial regrowth. In this paper, microstructures of amorphized, partially regrown and fully regrown layers are described in terms of extended-defect states of the material. Initial states (i.e. amorphized) and final states (i.e. solid-phase regrown and then reordered) are defined. Transmission electron microscopy and Rutherford backscattering/ion-channeling are the analytical techniques which are used in the characterization.